A growing concern exists for persons who are physically challenged or otherwise have limited mobility. That concern has given rise to the development of structures to accommodate such persons. Such developments have included the development of lifts for transporting occupied wheelchairs, and the like, in and out of vehicles. Typically, these lifts provide mobile platforms to raise and lower passengers between loading from outside the vehicles from a ground level and entry into the vehicles at a vehicle floor level.
Ramps have also been developed for enabling access into and out of vehicles. As concerning ramps which travel with the vehicles, these ramps are typically stored in the vehicles when not in use and deployed when it is necessary to provide passenger access. When such a ramp is deployed, the two ends are typically positioned at different heights. One end is usually adjacent the vehicle floor and the other end is usually on the ground. As such, depending on the terrain on which the vehicles are parked, a relative height difference exists between the vehicle floor and the ground, which may be quite substantial.
Since the passengers must travel across from one end of the ramp to the other, it is necessary that the ramp be fully deployable without obstruction by formations in the terrain. Also, when deployed, the ramp must provide a safe surface on which the passengers are supported while they travel across the ramp.
Proposed wheelchair ramps have included a platform which is pivotally connected at a lower edge to the vehicle floor. Such a platform is typically stored in an upright position and is thus deployed by swinging the platform outwardly from the vehicle about the bottom edge. Accordingly, the platform moves through a substantial range of motion, the upper edge starting from a relatively high position and ending at a relatively low position. With such a substantial range of motion, there may exists a danger of undesirable motions or displacements in which the platform may move to undesirable positions, or even free fall through space. As a result, persons nearby may sustain injuries.
Proposed wheelchair ramps have also included a ramp which translates from below the vehicle floor in a horizontal stored position to a deployed position where the ramp extends beyond the vehicle. Although these ramps may avoid the dangers associated with the other proposed wheelchair ramps and are relatively less complex in design, they are often difficult to operate. Where the terrain is particularly uneven and/or the vehicles utilizing the ramps have low vehicle floors (or low operational floors), the ramps often cannot be fully deployed. For example, where the vehicles are parked curbside, the curb often obstructs the translating ramps from reaching their full extension beyond the vehicles. This problem may be avoided by providing shortened ramps; however, shorter ramps can involve steeper surfaces on which the passengers must either ascend or descend in their wheelchairs. Consequently, there exists a need for a ramp assembly which is relatively simple in design and structure and avoids the dangers and difficulties of current vehicle ramps.